Hello Mansaul, I have a charge 3 right now, and I haven't experienced these issues, the display can be a bit rough to read when in direct sunlight but is otherwise ok. the display on the Charge 3 is backlit, according to the spec sheet. All modern digital displays are lit in some way. I have my brightness to normal, though I know that the level I get on the Charge 3 at normal is too dim for a lot of people; if you go into the device settings on the tracker, you will find the brightness; low is going to be far too dim most of the time, normal is what I find adequate, and you can also set it to high.
You can find official instruction from the manual (around page 16)
https://staticcs.fitbit.com/content/assets/help/manuals/manual_charge_3_en_US.pdf
If the Charge 3 is still too dim at the highest setting, it may be worthwhile to invest in a fitbit with a brighter screen. I know the Sense has an AMOLED screen, which is reported to be very bright, but I'm unsure of all the trackers - I have limited experience and I have not done the research. By no means am I suggesting to go from the lower end of the cost spectrum straight to the top - the purpose of pointing out the sense screen is that fitbit uses different display technologies across their line, so each unit will be different in how bright it is and what it can display, both in terms of color, clarity, and brightness. there's plenty of reviews for each product in the lineup, so I'd encourage you to look into each one that you may be interested in to try to see if the brightness of another unit may be more on-par with what you would like to see from your fitbit.
I hope this helps. Good luck.
